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提交 3186cd94 authored 作者: Serhij S's avatar Serhij S
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DataPolicy macro moved to rtsc

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roboplc-derive/Cargo.toml
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[package] [package]
name = "roboplc-derive" name = "roboplc-derive"
version = "0.1.9" version = "0.3.0"
edition = "2021" edition = "2021"
authors = ["Serhij S. <div@altertech.com>"] authors = ["Serhij S. <div@altertech.com>"]
license = "Apache-2.0" license = "Apache-2.0"
......
roboplc-derive/src/lib.rs
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extern crate proc_macro; extern crate proc_macro;
use proc_macro::TokenStream; use proc_macro::TokenStream;
use quote::quote; use quote::quote;
use syn::{parse_macro_input, Data, DeriveInput, Fields, Lit, Meta, MetaNameValue, NestedMeta}; use syn::{parse_macro_input, DeriveInput, Lit, Meta, MetaNameValue, NestedMeta};
/// Automatically implements the `DataDeliveryPolicy` trait for an enum
///
/// Atrributes (should be spcified for each enum variant):
///
/// * `data_delivery` - Specifies the delivery policy for a variant. The value can be one of the
/// following: `single`, `single_optional`, `optional`, `always`. If not specified, the default is
/// *always*.
///
/// * `data_priority` - Specifies the priority for a variant, lower is better. The value must be an
/// integer. If not specified, the default is *100*.
///
/// * `data_expires` - Specifies if the data expires. The value must be a function that returns
/// boolean. If not specified, the default is *false* (i.e. data does not expire). For named
/// associated data, the source MUST be stored in `value` field.
///
/// Example:
///
/// ```rust
/// use roboplc::DataPolicy;
/// use roboplc::ttlcell::TtlCell;
///
/// #[derive(DataPolicy)]
/// enum MyEnum {
/// #[data_delivery(single)]
/// #[data_priority(10)]
/// #[data_expires(TtlCell::is_expired)]
/// SensorData(TtlCell<f32>),
/// #[data_delivery(optional)]
/// DatabaseTelemetry(f32),
/// // the default one, can be omitted
/// #[data_delivery(always)]
/// Shutdown,
/// }
/// ```
///
/// # Panics
///
/// Will panic on parse errors
#[allow(clippy::too_many_lines)]
#[proc_macro_derive(DataPolicy, attributes(data_delivery, data_priority, data_expires))]
pub fn data_policy_derive(input: TokenStream) -> TokenStream {
let ast = parse_macro_input!(input as DeriveInput);
match ast.data {
Data::Enum(ref data_enum) => {
let enum_name = &ast.ident;
let mut delivery_policy_cases = vec![];
let mut priority_cases = vec![];
let mut expires_cases = vec![];
let mut default_policy_impl = true;
let mut default_priority_impl = true;
let mut default_expires_impl = true;
for variant in &data_enum.variants {
let variant_name = &variant.ident;
let mut priority_value = quote! { 100 };
let mut delivery_policy_value = quote! { ::roboplc::DeliveryPolicy::Always };
let mut expires_value = quote! { false };
for attr in &variant.attrs {
if attr.path.is_ident("data_delivery") {
default_policy_impl = false;
if let Meta::List(meta_list) = attr.parse_meta().unwrap() {
for nested_meta in meta_list.nested {
delivery_policy_value = match nested_meta {
NestedMeta::Meta(meta) => parse_delivery_policy(
meta.path()
.get_ident()
.map(|v| v.to_string().to_lowercase())
.as_deref(),
),
NestedMeta::Lit(lit) => match lit {
Lit::Str(lit_str) => parse_delivery_policy(Some(
&lit_str.value().to_lowercase(),
)),
_ => panic!("data_delivery value must be a string"),
},
};
}
} else {
panic!("unable to parse data_delivery attribute");
}
} else if attr.path.is_ident("data_expires") {
default_expires_impl = false;
if let Meta::List(meta_list) = attr.parse_meta().unwrap() {
for nested_meta in meta_list.nested {
if let NestedMeta::Meta(lit) = nested_meta {
expires_value = quote! { #lit(value) }
} else {
panic!("data_expires value must be a function",);
}
}
} else {
panic!("unable to parse data_expires attribute");
}
} else if attr.path.is_ident("data_priority") {
default_priority_impl = false;
if let Ok(Meta::List(meta_list)) = attr.parse_meta() {
for nested_meta in meta_list.nested {
if let NestedMeta::Lit(lit_int) = nested_meta {
priority_value = quote! { #lit_int };
} else {
panic!("data_priority value must be an integer");
}
}
} else {
panic!("unable to parse data_priority attribute");
}
} else {
panic!("Unknown attribute: {:?}", attr.path);
}
}
let pattern = match &variant.fields {
Fields::Unnamed(_) => quote! { #enum_name::#variant_name(..) },
Fields::Named(_) => quote! { #enum_name::#variant_name{..} },
Fields::Unit => quote! { #enum_name::#variant_name },
};
let pattern_expires = match &variant.fields {
Fields::Unnamed(_) => quote! { #enum_name::#variant_name(value, ..) },
Fields::Named(_) => quote! { #enum_name::#variant_name{value, ..} },
Fields::Unit => quote! { #enum_name::#variant_name },
};
delivery_policy_cases.push(quote! {
#pattern => #delivery_policy_value,
});
priority_cases.push(quote! {
#pattern => #priority_value,
});
expires_cases.push(quote! {
#pattern_expires => #expires_value,
});
}
let fn_delivery_policy = if default_policy_impl {
quote! {
fn delivery_policy(&self) -> ::roboplc::DeliveryPolicy {
::roboplc::DeliveryPolicy::Always
}
}
} else {
quote! {
fn delivery_policy(&self) -> ::roboplc::DeliveryPolicy {
match self {
#(#delivery_policy_cases)*
}
}
}
};
let fn_priority = if default_priority_impl {
quote! {
fn priority(&self) -> usize {
100
}
}
} else {
quote! {
fn priority(&self) -> usize {
match self {
#(#priority_cases)*
}
}
}
};
let fn_expires = if default_expires_impl {
quote! {
fn is_expired(&self) -> bool {
false
}
}
} else {
quote! {
fn is_expired(&self) -> bool {
match self {
#(#expires_cases)*
}
}
}
};
let generated = quote! {
impl ::roboplc::DataDeliveryPolicy for #enum_name {
#fn_delivery_policy
#fn_priority
#fn_expires
}
};
generated.into()
}
_ => panic!("DataPolicy can only be derived for enums"),
}
}
fn parse_delivery_policy(s: Option<&str>) -> proc_macro2::TokenStream {
match s {
Some("single") => quote! { ::roboplc::DeliveryPolicy::Single },
Some("single_optional") => quote! { ::roboplc::DeliveryPolicy::SingleOptional },
Some("optional") => quote! { ::roboplc::DeliveryPolicy::Optional },
Some("always") => quote! { ::roboplc::DeliveryPolicy::Always },
Some("latest") => quote! { ::roboplc::DeliveryPolicy::Latest },
Some(v) => panic!("Unknown policy variant: {}", v),
None => panic!("Policy variant not specified"),
}
}
fn lowercase_first_letter(s: &str) -> String { fn lowercase_first_letter(s: &str) -> String {
s.chars() s.chars()
......
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